The present invention relates to a method of manufacturing a magnetic head for a magnetic disk drive unit.
A conventional magnetic head for a magnetic disk drive unit is manufactured by the steps of: forming a plurality of layers including a magnetizable layer on a substrate, which is a wafer made of a ceramic, e.g., Al2O3TiC; cutting the wafer to form a plurality of raw bars; lapping the raw bars; forming air bearing surface patterns on ABS faces of the raw bars; and cutting the raw bars to form sliders.
A thickness of the conventional wafer is equal to or slightly greater than a length of the slider. Note that, the length of the slider is indicated by a symbol “L” in FIG. 8. If the thickness of the wafer is greater than the length of the slider, a rear face of the wafer is abraded to make the thickness of the wafer equal to the length of the slider, then the wafer is cut to form the raw bars. Note that, in the following description, a width of the raw bar means the length of the slider.
These days, recording density of magnetic disks have been higher, so that sizes of sliders of magnetic heads must be small. Sizes of the conventional sliders, e.g., a nano-slider, a pico-slider, a femto-slider, are shown in TABLE.
TABLELengthThicknessLength of Raw BarSliderL (mm)D (mm)(mm)nano-sliderabout 2.050.4040–50pico-sliderabout 1.250.3040–50femto-sliderabout 0.850.23–0.3540–50
As shown in TABLE, the length of the smallest sliders is less than 1 mm, and the thickness thereof is 0.2–0.3 mm. A plurality of sliders are formed in each raw bar, which is formed by cutting the wafer, and the length of the raw bar is considerably long with respect to the width and the thickness thereof. Since the raw bars are long and thin, rigidity and machining accuracy of the raw bars must be lower.
When the raw bars are machined, the raw bars are adhered onto a supporting jig. If the rigidity of the raw bars are low, the raw bars are bent and curved by remaining stress, which is caused in a step of forming the layers, so that the machining accuracy must be lower.
By the deformation of the raw bars, the raw bar cannot be correctly set in the supporting jig, so that treatment of the ABS faces, e.g., photolithography, cannot be executed precisely. Since the raw bars are small, it is difficult to clean the raw bars and set them onto the supporting jig correctly, so that edges of the raw bars are apt to be damaged and yield of manufacturing the sliders must be lower, further it takes a long time to correctly set the raw bars onto the jig.